Engine starting turbine having combustion element supplied thereto in response to speed and combustion chamber pressure



, m er obj ects; oi the Patented Mar. 17, 1953 PATENT QFFICE ENGINESTARTING TURBINE -HAYINGCOM-a BIlLSIlION; ELEMENT. SUPPLIED 'rmmn'ro IRESPONSE TO SPEED AND ooMnUs-v HON-CHA B R PRESSURE.

Gharles S; Jewett; Ramsey, N.' J;, assignor to Curtiss-Wright;Corporation, a corporation, of

n l w l' Application July :7, 1948', Serial No. 37; 104: 15. am... (01.60-3914.)

Th s; nven ion; re a es i n ne a s aricular dir tt is J r -arr ratu mcrankmg or, turning; over large; aircraft 7 engines.

The pnyenfio ell rmo r r t se t t.-

etwmn se a-n elect i mo o a n e to ec its; energy; f-rom. an electricbattery. Modern large aircraft engines,howevenrequire such large amountsof energy-for starting, that this 1 conventional; form of starter; isimpractical This. iS

particularly. true of gas. turbine. engines which, in 10 contrast withreciprocating engines,- must be cranked at high speeds,- in the.neighborhood of;1 0 0;to2 (l(l0 1'1? -.Ba M by the starting apparatus.

object. of; this inventionco-mprises. the provision of; novel; startingapparatus. capable of quickly-bringing; such an; engine up to itsrequired starting speed. turtherobject of, the. invention comprises theprovision of starting apparatus haying; means for; automaticallycontrolling the magnitudeof its torque. output.

The enginestarting apparatus shouldbecapable oi} bringing, the, engineup. to. its required starting;speed in as short a time as possible andat the same time the output torque of said apparatus should be keptbelow a predetermined upper-limit in order notto overload the gears andother-transmission. means of the engine. Specifically; the starting,apparatus of the invention comprises asingle-stage impulse-type gasturbine enginelwith control means therefor. It has been so determinedthat, i fthe temperature ofits. motive fluid is constant, the torqueoutput of, such an engine remains substantially constant, regardless ofvariationsin its speed,if; the pressure of its motive .fluidis varied,approximately. as the, square of its ,-speedl Accordingly it is a.further object, I of the invention to provide automatic means forcontrollingthe pliesfsu rev of. the motive. fluid. of the. startingturbine. with changes in. itsv speed.

A; still further object of theinvention'relates 40 the ixtur sup ie to teicpmbi st nlcham btr-qe nee s ur i a a erens ne. r. bus- 219 -re n, Apl c n h s et rmin d h t. a

combustion mixture,v comprising gasoline. orother hydrocarbon fuel andhydrogen peroxide-, having 451 a-concentration of 40 to '70 7; in water,has numerous desirable properties, Thus, the gasoline and hydrogenperoxide. can; be. separately stored atlowpressures and onlysmallvolumesof each arev required. for each starting operation. Alsowithin said: concentration. range, the freezing p int. of: th hydros n;peroxide is below. 40? F. and thehy drogen; peroxide isquite safe,itsmaximum temperatureupon decomposition. being less than 400 F. Inaddition, thehydrogenpemxide is. relatively cheap contributes tov theheat oi, so. busti n.of. beh dm a on uel a p ov d to 'mtev nt excessicombust on mper scriptionin connection with the drawing which m risesaematic v e a t r in p a atus embodying the invention.

Ref inew t e dra ing he s a ti a p ratus comprises a conventionalsingle-stage impulse u b wh ch s ar aneedio r ve a hj f i l of an engineto. be started, through reductiongears I 4,, l6, l8, andZ U and aone-way clutch 1 2 The one-Way clutch 22, is arranged so that thestarterturbine It can drive the engine shait IZ- but; so that the enginecannotdrive said turbine. The turbine IILis arrangedto be driven by combustiongases generated in the combustion chamber 24 ndsu p e o. a. urb zz e -1invention is. primarily concerned with the elementsv of combustionsupplied to the combustion c a be M nd. t m a rar u mir l in theirrates. of supp y to said chamber.

In accordance with the invention, hydrogen perox an s sq inaor. he xdroar sa n ar supp ied to he q mbusfi qn hamb .4. for combus i n he ein. sr n. s d. Sa u l. nd the hydrogen peroxide are both termed cornbustionelement, Gasoline is particularly suitle or use n. an ai -cr f n S a tebecause itis readily available wherever airplanes ar bas d. and. e ausof ish wt o t tl-Iydrogen peroxide is particularly suitable for usexxritl a hydrocarbon fuel because it contains the oxygen necessary forcombustion of said fuel, thereby eliminating the need for anaircompressor. The cost of, the, hydrogen peroxide is lso lat ve y l w andbeing a i u it n. b readily stored andhandled. In addition thehydrogenperoxide contributes to the heat released durin comb s o an f she er f pventing excessive combustion temperatures. In

Y c nvention l st rb e n in wh h o pressed. air is mixed with ahydrocarbon fuel for QQIEPUWQ L, ibis ece a mi ar mo nt or excess airwiththe combustion gases in order th tt e tem erat o h c m i ea s breduced to a point below the maximumsa feoperating temperature of theturbine rotor. I

Hydrogen, peroxide has a minimum freezing point of approximately 67 F.at approximately concentration inwater. Atboth higher and lower hydrogenperoxide concentrations; its ireez- .ing point ishigher than 67 F.Between approximately 40 and 70% concentration, thefreezing pointofhydrogen peroxide in water is below +49? F... so that tor mostaircraftoperation hydr s n peroxide an e s d at a c n tn ti w thi th s an e whput an d ng i. it r mg.

Hyd o en. peroxide ecomposes qui e. di y in o oxygen. and water a 9 1 tiv 1; lar e moun q ene gr he final m ra..-

t e. r su tqf the 'tom f s re... .xide de ends 0. 2 ip t altonhis?! tncentra s iffln temperature may be as high as 1300" F. Ac-

cordingly, high concentrations of hydrogen per-.

tration of the hydrogen peroxide and at 70% concentration saidtemperature is approximately 400 R, which temperature is stillrelatively safe. Accordingly, the use of a combustion mixture comprisinga hydrocarbon fuel, such as gasoline, and hydrogen peroxide in water, inconcentrations between 40 and 70%, is particularly suitable for use ingas turbine engines intended for aircraft use.

Hydrogen peroxide is stored in the tank 2 6 from which it is supplied tothe combustion chamber 24 through a passageway 28, said passagewayhaving a valve 30, a restricted orifice 32 and valves 34, 36, and 38.Gasoline or other hydrocarbon fuel is stored in the tank 40 from whichit is supplied to the combustion chamber 24 through a passageway 42,said passageway containing a valve 44, a manually controllable valve orrestriction 46, and a valve 48. The combustion chamber 24 is providedwith suitable igniter means 49 for igniting the combustion mixture ofgasoline and hydrogen peroxide supplied thereto.

Carbon dioxide under pressure is applied to the surfaces of the hydrogenperoxide and gasoline,

,in their respective tanks, for forcing or pump- ,ing said liquidsthrough their respective passageways 28 and 42 to the combustion chamber24. For this purpose, a conduit 58 is connected to a suitable source ofcarbon dioxide under pressure from which said carbon dioxide is suppliedto a pair of valves 52 and 54 under the control of a conventionalpressure regulating valve 55.

.The pressure regulating valve 55 maintains a substantially constantpressure on its downstream side. The valves 30. 44, 52 and 54 and afifth valve 56 are all pivotally connected to a link 58 which is adaptedto be operated by a solenoid 62.

The solenoid 62 is connected to a suitable source of electric energy 64throu h a switch 66. The

switch 66, when closed. effects energization of the solenoid 62 to movethe link 58, and the valves 30. 44, 52, 54. and 56 to their ositionsillustrated. In the positions illustrated, the valves 52 and 54 admitcarbon dioxide under pressure from the conduit 50 to the tops of thehydrogen peroxide and fuel tanks through passages 68 and [8respectively. open for transmitting hydrogen peroxide and fuel, undersaid carbon dioxide pressure, from their respective tanks to thecombustion chamber 24. When the solenoid 62 is de-energized, the link 58is moved to its dotted line position thereby closing the hydro enperoxide and fuel valves 30 and 44. In addition, de-energization of thesolenoid 62 results in movement of the valve 52 to its dotted lineposition in which the top of the hydrogen peroxide tank 26 is ventedthrough the conduit 68 and a vent opening 12.

. Similarly, the valve 54 is moved to its dotted line 4 position to ventthe top of the fuel tank 46 through the conduit 10 and a vent opening14.

From the valves 30 and-4.4. the hydrogenpe'roxide' and fuel flow throughtheir respective In addition, the valves 36 and 44 are orifices 32 and46, said orifices forming part of a flow proportioning mechanism,indicated in its entirety by the dashed line 76. The flow proportioningmechanism 16 also includes the valve 48 in the passageway 42, said valvebeing connected, by means of rods 18 and 80, to the flexible diaphragms82 and 84 for automatic control thereby. The flexible diaphragm 82divides a housing 86 into a pair of chambers 88 and 90, the chamber 88being connected by a conduit 92 in communication with the passageway 28immediately downstream of its restricted orifice 32. The flexiblediaphragm. 84 divides a housing 94 into a pair of chambers 96 and 98,the chamber 38 being connected by a conduit I00, in communication withthe passageway 42 immediately downstream of the restricted orifice 46.The same fluid pressure acts on the other sides of the diaphragms 82 and84. Thus, when the solenoid 62 is energized to supply hydrogen peroxideand fuel to the combustion chamber 24, the valve 56 admits carbondioxide from the supply conduit 50 through a conduit I02 to the chambers98 and 96. When the solenoid 62 is de-energized to shut off saidhydrogen peroxide and fuel, the chambers and 96 are both vented by thevalve 56 through the conduit I02 and a vent opening I64. Accordingly,since the diaphragms 82 and 84 have the same area and are connected bythe rod 80, the fluid pressure in the chamber 90 always balances thefluid pressure in th chamber 96.

The arrangement of the flow proportioning mechanism I6 is such that thepressure of the hydrogen peroxide in the passageway 28 immeatelydownstream of the restriction 32 acts on the diaphragm 82 to urge thevalve 48 in a closing direction while the pressure of the fuelimmediately downstream of the valve 46 acts on the diaphragm 84 to urgesaid valve in an opening direction. The flexible diaphragms 82 and 84have the same effective area so that the valve 48 automaticallymaintains the pressure of the fuel immediately downstream of thevariable restriction 46 equal to the pressure of the hydrogen peroxideimmediately downstream of the fixed restriction 32. Except for smalldifferences in the head of liquid, the same liquid pressure exists onthe upstream sides of said restrictions 32 and 46 since the carbondioxide pressure in the hydrogen peroxide tank 26 is the same as that inthe fuel tank 40. Accordingly, the valve 48 automatically operates tomaintain the fluid pressure drop across the variable restriction 46equal to that across the fixed restriction 32. Therefore, the proportionof hydrogen peroxide and fuel supplied to the combustion chamber 24depends on the relative size of the restricted open ings 32 and 46 and,for any given setting of the variable restriction 46, the valve 48 willautomatically operate to maintain a predetermined ratio of fuel flowthrough the passageway 42 to the flow of hydrogen peroxide through thepassageway 28. This ratio can be increased or decreased by an opening orclosing adjustment, respectively, of the variable restriction 46as forexample would be desirable if the concentration of the hydrogen peroxidewere respectively increased or decreased.

When hydrogen peroxide and fuel are being supplied to the combustionchamber 24, the pressure immediately downstream of the restrictions 32and 46 is always less than the equal pressures existing immediatelyupstream of said restrictions. Accordingly no matter how high the hy-"drogen peroxide pressureis downstream of the restriction 32, the valve48 can always move'ina closing direction to provide an equal fuelpressure downstream of the variable restriction '65.

However, in the 'abse'nceof the valve 34,'a situa- 'tion might arisewhere the pressure downstream oi the restriction 32 is so low that, evenif the valve48 were fully open,'the pressure downstream of therestriction 4-6 would be higher. To prevent this unbalance of the flowproportioning mechanism I6, the valve 34 is providedto main- "tain atleast a predetermined back pressure on the fixed restriction 32. Forthis purpose, the "valve 34 is connected'to a flexible-diaphragm I96.dividing'a'housing I08 intoapair of chambers III) and H2. The chambersIll] and H2 are con- :nected tothe upstream and downstream sidesrespectively o'fv the valve 34 soth'at thepressuredifzferenceacrossxsaid valve'urges said valve in an opening directionagainst a spring H4. With this arrange nent the spring I Idinsures apredeterm'inedpressure drop across the valve 34 whenever hydrogenperoxide flows'therethrough, thereby preventing-the hydrogen peroxidepressure, on the downstream side or the restriction 32, from fallingbelow a predetermined value.

, 92. With such an arrangement, however, if said "singlediaphragm shouldbreak or leak, premature mixing and combustion of the fuel and hydrogenperoxide might take place. With the double diaphragm constructionillustrated, breakage of either the diaphragm82 'or'the diaphragm 84resultsorilyin mixture o'ffuel or hydrogen peroxide with the inertcarbon dioxide.

."T0rque outputs of the starter turbine II), below the design value,"will. crank the engine shaftfIZ "too slowly while excessive torqueoutputs of the "turbine III will overload the gear teeth in the"power-plant. Accordingly, itis essential to provide some means forcontrolling the torque output of "the starter turbine Ill. The torqueout- .put of an impulse turbine depends not only on the mass .rate :offlow of the turbine motive fluid, "but also "on the change in momentumof that fluid at the rotor blades 'of the turbine. This change inmomentum varies with changes in the tangential velocity or speed ofrotation 'of said "rotor blades, so that meansareprovided forcompensating for this change in momentum with changes inv turbine speed.It can be shown that the torque output'of a single stage impulse turbinewill remain substantially constant if the pressure of its motive fluid,upstream of the'turbine rotor blades, is varied as the square of, the

' speed 'of said-turbine, provided "the temperature or said motive fluidremains substantially constant. 'Sincethe ratio of the rates 'at whichhydrogenperoxide and fuel are supplied'to the combustion chamber 24 ismaintained'substantially constant by the flow proportioning mechanism'IB,-the temperature within the combustion cham ber 24 will remainsubstantially constant provided the concentration of the hydrogenperoxide and "the initial temperatures of the hydrogen peroxideandzfuelremain substantially constant. The torque output of the starter turbineII] is regulated by the valve 38 under the control of a speed responsivemechanism III). In addition, 'saidspeed responsive mechanismItllcontrolsthe valve 36 for preventing over-speeding of the starterturbine =I0 -during=no-1o'ad operation- -for example after the powerplant has started.

'matically indicated by the dashed line I22.

and a piston I26 is slidable within said bore.

The speed responsive mechanism H0 comprises a fixed housing M2 to whicha suit-ablefluid under pressure :is supplied. Preferably, carbon dioxidefrom the supply line 50 is used as said fluid. As illustrated, when thesolenoid 62 is energized,

carbon dioxide under pressure is admitted by the valve 56 into thehousing H2 via the conduit I02 and a conduit "H5. A member H6 isrotatably mounted withinthe housing I I2 by trunnione I I8 and limitsmovement of the piston I26 toward said bore end so that, whenthe memberH6 rotates, the centrifugal force acting on the piston I25 always'urgessaid piston toward ithejother'or head end of saidbore.

Thepiston "I 26 hasan annular groove I which communicates with the headend of said piston through passages I32 and I34. Upon movement of thepiston I26 toward said head end, its groove I31! registers with apassage I36 in the rotatable member IIS, whereupon the fluid pressurewithin the housing I I2 is admitted to the head end of the bore I24,through the passages I32 and I34, until said pressure is sufficient tobalance the centrifugal force acting on the piston I26.

The end of the bore I24 adjacent the amtment I23 is vented throughpassages I40 and I42. In addition, movement of the piston I26 towardsaid abutment moves the annular piston groove I39 out of registry withthe fluid pressure passage I3I5 and into registry with the vent passageIrlZ. Accordingly, whenever the speed of rotation of the member H6decreases the fluid pressure acting against the head end of its pistonP26 moves said piston toward its abutment end whereupon the annularpiston groove I30 registers with the vent passage I42 thereby relievingsome of said pressure until said pressure and the centrifugal forceacting on the piston are again in balance. With this construction, whenthe member I I6 is rotated anda fluid pressure is supplied to thehousing H2, the piston I 26 automatically assumes a position such thatthe centrifugal force acting thereon is balanced by the fluid pressureacting against the head end of the piston I26. The centrifugal forceacting on the piston I26 is proportional to the square of the speed ofrotation of the member Ht within which the .piston'is slidable.Therefore, since'the rotatable member H6 'is driven by the turbine II],the. fluid pressure acting against the head end of the piston I26 variesas :the square of the speed of rotation of the turbine III whereby themechanism 'I'IO provides a fluid pressure signal which is proportionalto the square of the speed of said turbine.

In the balanced or neutral position of the piston I25 its groove I30 isdisposed between the fluid pressure passage I36 and the vent passage I42 so that slight radiall outward movement of said piston moves itsgroove I38 into registry with the fluid pressure passage I36 and slightradially inward movement moves said groove into registry with the ventpassage I42. Therefore, during operation of the starting apparatus, therange of movement of the piston I26 is small so that said annular grooveI39 is continually in communication with a p'assagewayM I extendingthrough the trunnion H3, said passageway I44 communicating with aconduit 'l 4 6.

The conduit I46 opens into one side of a. housing I48 having a flexiblediaphragm [50 extending thereacross. The other side of said housing isvented through an opening F52 and said diaphragm IE is connected by arod I54 to the valve 38. A spring 158 urges the valve 3-6 toward itsopen position. The fluid pressure acting against the head end of thepiston 125 is transmitted therefrom through the passages I32 and I34,the piston groove I36, the passage M4 and the conduit I46 to thediaphragm I50 for urging the valve 36 in a closing direction against thespring I58. The arrangement is such that the valve 3-3 remains in itsfull open position unless the speed of the turbine It) becomesexcessive. When the speed of said turbine exceeds a predetermined highvalue, the fiuid pressure acting against the diaphragm Hill becomessufficient to move the valve 36 in a closing direction against thespring I58, thereby reducing the rate at which hydrogen peroxide issupplied to the combustion chamber 24. Closing adjustment of the valve36 not only results in a reduction in the rate at which hydrogenperoxide is supplied to the combustion chamber 24 but the fiowproportioning mechanism 16 effects a corresponding reduction in the fuelflow to said chamber thereby decreasing the speed of the turbine 50.

The valve 3-3 is also controlled by the speed responsive mechanism ill.For this purpose, the valve 38 is connected by a rod I60 to a flexiblediaphragm I62 which divides a housing into a pair of opposed chambers 54and I68. A spring Hi8 urges the valve 38 in an opening direction. Thechamber 164 communicates with the combustion chamber 24 through aconduit Hi! whereby the pressure with-in said combustion chamber istransmitted through the conduit 110 as a pressure signal to the chamber154 where said pressure acts against the diaphragm I62 to urge the valve38 in a closing direction. The chamber I 6'6 communicates with the fluidpressure acting against the head end of the piston 126 through a conduitI12, the conduit ME, the passage M4, the annular piston groove I30, andthe passages I32 and L34. Accordingly, the fluid pressure acting againstthe head end of the piston I26 also acts against the diaphragm 162 tourge the valve 38 in an opening direction. Substantially coincidentalwith any change in the rate of flow of hydrogen peroxide to thecombustion chamber 2 3 as a result of operation of the valve 38, thevalve 48 of the fiow proportioning mechanism H operates to effect asimilar change in the flow of fuel to said chamber. Therefore, the valve38, together with the flow proportioning mechanism 16, operates tocontrol the rate at which hydrogen peroxide and fuel are supplied to thecombustion chamber 24 so that, except for the force of the spring lEB,the pressure within the combustion chamber 2'4 is maintainedsubstantially equal to the fluid pressure acting against the head of thepiston I26. This latter fiuid pressure is proportional to the square ofthe speed of the turbine is. Accordingly, the pressure automaticallymaintained within the combustion chamber 24, by the valve 38, is equalto an initial pressure, determined by the spring [68, plus a pressurewhich is a function of or varies substantially as the square of thespeed of the turbine If).

It is proposed. to provide an initial pressure of 60 p. s. i., aboveatmosphere, in the combustion chamber 24 when the speed of the turbineis zero. This pressure is determined by the spring 16B. In order todischarge fuel 'and hydrogen peroxide into the combustion chamber 24,the pressure of the carbon dioxide should be such as to supply the fueland hydrogen peroxide to said combustion chamber at a pressure above thecombustion chamber pressure-for example at pressures from 10 to 20atmospheres. Obviously the initial pressure in the combustion chamber 24and the pressure at which fuel and hydrogen peroxide are supplied tosaid chamber are subject to considerable variation.

When the starting apparatus is used for cranking an aircraft engine, thestarter turbine 10, the reduction gear connecting said turbine to theengine shaft I2, the combustion chamber 24, and the speed responsivemechanism H0 with the valves controlled thereby, must all be mounted onthe aircraft. The flow proportioning mechanism 16, the tanks 26 and 40,the supply of carbon dioxide, and the solenoid operated valves, may alsobe mounted on the aircraft or this latter mechanism may be mounted on asuitable ground vehicle.

If this latter portion of the starting apparatus is mounted on theaircraft, it may be connected to a plurality of starter turbines ID bysuitable valves. In addition, the fuel tank 40 is preferably filled withgasoline from the aircraft tanks by means of a conduit I14 and a lowpressure pump (not shown) on the. aircraft. A check valve H6 is providedin the conduit I14 to prevent reverse fiow of gasoline out from the tank40 through said conduit. The tank 40 is also provided with a flexiblediaphragm I18 extending thereacross to prevent the tank 40 from beingfilled to overflowing.

Where, however, the flow proportioning mechanism 16, the tanks 26 and40, the source of carbon dioxide, and the solenoid operated valves, areto be mounted on a ground vehicle then, in order to complete theapparatus for starting an aircraft engine, the portions of the passages28 and 42 and the conduit H5 onthe ground vehicle must first beconnected to the remaining portions of said passages and conduit on theaircraft. Obviously, however, the operation of the starting apparatus isthe same whether all or only a portion of said apparatus is mounted onthe aircraft.

While I have described my invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the appended claims to cover all such modifications.

I claim as my invention:

1. A fuel system for a gas turbine engine having rotor for providingengine starting torque; said system comprising means for supplying afirst combustion element to the combustion chamber of said engine; meansfor supplying a second combustion element to the combustion chamber ofsaid engine, one of said combustion elements being a hydrocarbon fueland the other of said combustion elements being hydrogen peroxide of 40to 70% concentration in water; first regulating means operable to varythe flow of one of said combustion elements to said combustion chamber;means responsive to the speed of said rotor for providing a first forcewhich increases with increase in said speed; means operatively connectedto said first regulating means and subjected to said first force forurging said regulating means in airflow increasing directionandsubjected to a second force. proportional to the pressure in saidcombustion chamber ,for urging saidrfirst regulating means in a flowdecreasing direction; second regulating means op- 'erable, to vary theflow rate at which the other combustion element is supplied to saidcombustion. chamber; and means for efiect'ing operation of" said secondregulating means substantially coincidental with operation of said firstregulating means such that a change in the rate of flow of said onecombustion element result.- ing from operation ofsai'dfirstregulatingmeans is accompanied'by a similar change in the rate 'of' flowof said other combustion element;

2; A fuel system for a gas turbine engine having; a combustion chamber;means for regulat ing'the rate of supply of a; combustion element tosaid combustion chamber; means-providing a first force whichincreases'with increase in speed of said. engine; means providing asecond" force which increases with increase inpressure in saidcombustion chamber; and means for, controlling said regulating meanssuch that an increase of said first force and a decrease of said secondv forceboth tend to enact an increase in the rate ofisupnly of, saidcombustion element.

3.. j Engine starting apparatus comprising a gas turbine having acombustion chamber and having a .rotor forv providing engine startingtorque; means for regulating the flow of a combustion element to saidchamber; means providing a first force which increases with increase inthe speed of said turbine rotor; means operatively connected to said;fiow regulating means and subjected to said first force for urging saidflow lregulatinghmeans 'in,a flow increasing direction; andmeansproviding a second force, said oneratively connected. means also beingsubjected to said second force for urging. said new regulating meansin..a flow decreasing direction.

4;. Engine starting apparatuscomprising a gas turbine, having acombustion chamber and havinga rotor for providing engine startingtorque;

means for regulating the flow of a combustion element to said chamber;means responsive to regulating means in a flow decreasing direction.

5. Engine starting apparatus comprising a single-stageimpulse gasturbinehaving a combustion chamber and having a rotor for providing enginestarting torque; means for regulating the flow of the combustionelements to said chamber; mechanism including means drivablylconnectedto saidrotor for providing afirst force proportional to thesquare of the speedof said rotor; and means operatively connected tosaid flow regulating means andrsubjected to said-first .force. forurging said. fiow regulating means in a flow. increasing directionv andsubjected to a second force proportional to the pressure with- .in-Jsaidchamber for urging said flow regulating means in a flow decreasingdirection.

6. Enginestarting apparatus comprising a gas .turbine having acombustionchamber and having'a rotor for providing engine starting torque; meansfor. regulating thefiow of a combustion element to said chamber; meansresponsive, to

the speed of said rotor-for providinga fluid pressureJproportional' tothe square of' said speed; means for urging said fiowregulating' meansin a flow increasing direction with a first force pro-- portional tosaid fluid pressure; and means'for urging said flow-regulating means-ina flowdecreasing directionwith a second force proportional tothecombustion chamber pressure:

"7-. Engine starting apparatus as recited in claim 6 and includingyieldable means biasing said flow regulating means in a flow increasingdirection.

8: Engine starting apparatus comprising a gas turbine having acombustionchamber and havingarotor for providing engine star-tingtorque; means forregulating the fiow of a combustion element to said chamber; a rotatablemember drivably connected to said rotor, said rotatable member having abore transverse to its axis of rotation; "a piston slidable along saidbore and urged in one direction therealong by the centrifugal forceacting on said piston; means including said rotatable member and pistonproviding a fluid pressure balancing thecent-rif-uga'l force acting onsaid piston; means for urging said flow regulating means in a flowincreasing direction with. a force proportional to said fluid pressure;and means for urging said fiow regulatingmeansina fiow. decreasingdirection with a forceproportional to the. combustion chamber pressure.

9. Engine starting apparatus comprising a gas turbine having, acombustion chamber and having. a rotor for providing engine starting.torque;

means for regulating the flow of a combustion element to said chamber;means responsiveto the speed of said;r.otor for providing a first: forceproportional to the .squareof. said speed; means inssaidflow.

10; Engine starting apparatus: comprising: a gasturbine havingacombustion chamber and having a rotor. for providing engine startingtorque; a container for hydrogen peroxide;.a container fora hydrocarbonfuel; saido'hydrogen peroxide and fuel eachv being aoombusticn ele-Iment for combustionin said chamber; mean for imposing a gaspressureonithe' combustion element in: eachsaid-container; first regu atingmeans operable tcvary the flow rate-at whic one of said combustionelements is :suppliedto said combustion chamberqby the gaspressure.inthe container of said-one: combustion. element;

means vresponsive to the speed, of said: rotoryand to the combustionchamber pressure and operatively connected to said first, regulatingmeans such that anincrease of said: speed and as decrease of. said.combustionchamber pressure -;-each tends to produce an increaseintherate of flow of said first combustion element; second regulating,means operable to vary theflow rate at which the other combustionelement is supplied to saidv combustion chamber by the gaspressure inthe container of said. other combustion element; and means for effectingoperationv .of said secondv regulating means substantiallyv,coincidental with operation of said firstregulating means suchvthat achange in the .rate of flow of said one combustionuelement resultingfrom 11 7 operation of said first regulating means is accompanied by asimilar change in the rate of flow of said other combustion element.

11. Engine starting apparatus comprising a gas turbine having acombustion chamber and having a rotor for providing engine startingtorque; means for supplying first and second combustion elements to saidcombustion chamber for combustion therein, one of said combustionelements being a hydrocarbon fuel and the other of said combustionelements being hydrogen peroxide of 40 to 70% concentration in water;mechanism .including means drivably connected to said rotor 'forproviding a fiuid pressure proportional to the square of the speed ofthe rotor; first regulating means controlled by said fluid pressure andby the pressure in said combustion chamber and operable to vary the rateof supply of one of said combustion elements to said combustion chamber;and second regulating means operable substantially coincidental withoperation of said first regulating means to vary the rate of supply ofthe other combustion element to said combustion chamber, the operationof said first and second regulating means being such that an increase ofsaid speed proportional pressure and a decrease of said combustionchamber pressure each tends to produce an increase in the rate of supplyof each of said combustion elements to said combustion chamber.

12. Engine starting apparatus comprising a gas turbine having acombustion chamber and having a rotor for providing engine startingtorque;

means for supplying first and second combustion elements to saidcombustion chamber, said elements forming a combustible mixture withinsaid chamber forcombustion therein; first regulating means operable tovary the flow rate at which one of said combustion elements is suppliedto said combustion chamber; means responsive to the speed of said rotorfor providing a first force which increases with increase in said speed;means operatively connected to said first regulating means and subjectedto said first force for;

urging said regulating means in a fiow increasing direction andsubjected to a second force proportional to the pressure in saidcombustion chamber for urging said first regulating means in a flowdecreasing direction; second regulating means operable to vary the flowrate at which the other combustion element is supplied to saidcombustion chamber; and means for effecting operation of said secondregulating means substantially coincidental with operation of said firstregulating means such that a change in the rate of flow of said onecombustion element resulting from operation of said first regulating'means is accompanied by a proportionate change in the rate of flow ofsaid other combustion element.

13. Engine starting apparatus comprising a gas turbine having acombustion chamber and having a rotor for providing engine startingtorque; means for supplying first and second combustion elements to saidchamber, said elefbustion element to said chamber; means for regulatingthe rate of supply of said second combustion element to said combustionchamber;

'means responsive to the speed of said rotor for 12 providing a firstforce proportional to the square of the speed of said rotor; and meansoperatively connected tosaid fiow regulating means and subjected to saidfirst force for urging said flow regulating means in'a flow increasingdirection and subjected to a second-force proportional to the pressurewithin said chamber for urging said flow regulating means in a flowdecreasing direction.

14. Engine starting apparatus comprisin a gas turbine having acombustion chamber and having a rotor for providing engine startingtorque; regulating means operable to vary the flow of a combustionelement to said combustion chamber; means providing a signal which is ameasure of the speed of said rotor; means providing a signal which is ameasure of the pressure in said combustion chamber; and means responsiveto said signals and operatively connected to said regulating means suchthat an increase of said speed and a decrease of said pressure eachtends to cause an increase in the rate of fiow of said combustionelement to said chamber.

15. Engine starting apparatus comprising a gas turbine having acombustion chamber and having a rotor for providing engine startingtorque; first regulating means operable to vary the fiow oi a firstcombustion element to said combustion chamber; means providing a signalwhich is a measure of the speed of said rotor; means providing a signalwhich is a measure of the pressure in said combustion chamber; meansresponsive to said signals and operatively connected to said firstregulating means for effecting operation of said first regulating meanssuch that an increase of said speed and a decrease of said pressure eachtends to cause an increase in the rate of fiow of said first combustionelement; second regulating means operable to vary the flow of a. secondcombustion element to said chamber; and means for effecting operation ofsaid second regulating means substantially coincidental with operationof said first regulating means such that a change in the rate, of flowof said first combustion element resulting from operation of said firstregulating means is accompanied by a proportionate change in the rate offiow of said second combustion element.

CHARLES S. JEWET'I.

.REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES PowerPlant Engineering, Jan.1947, pp. 78

and 79.

. Coast Artillery Journal," Jan.-Feb. 1948, pp. 27 and 28.

